This is a combined neuropharmacological and neurophysiological investigation aimed at gaining insight into the influence of neurotransmitters on the receptive field properties of frog retinal ganglion cells. We will inject the neurotoxin six-hydroxydopamine (6HDA) intravitreally to remove the dopaminergic innervation of the retina. Then we will examine the receptive field properties of ganglion cells in these retinas. The effects of perfusion with drugs thought to act on other retinal neurotransmitter systems will also be studied. A developmental study is also planned using 6HDA intraocularly in tadpoles. Recordings will be made from ganglion cells from adult frogs who were deprived of dopamine early in development. We hope to be able to expand our studies to include other compounds such as a "suicide inhibitor" of glutamic acid decarboxylase in order to study the effects of removal of other retinal neurotransmitters. Investigation of the pharmacology underlying retinal receptive fields can increase our understanding of developmental diseases of the eye.